Evaluation of Dyspnea

Variable Definitions Of Dyspnea Unpleasant or uncomfortable respiratory sensations Difficult, labored, uncomfortable breathing Awareness of respiratory distress The sensation of feeling breathless or air hunger An uncomfortable sensation of breathing ATS guidelines: subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity ATS. AJRCCM, 1999.

Variation In Symptoms of Dyspnea by Condition Manning. NEJM, 1995.

Respiratory Control Systems Designed to maintain gas exchange equilibrium and acid base status Abnormalities in this system -> dyspnea-> severe patient distress

Mechanisms Of Dyspnea: Respiratory Center Output Chemoreceptors Peripheral: carotid bodies, aortic arch Sense changes in PO2, acidosis, hypercapnea Central: medulla pH and PCO2 changes Hypercapnea Potent stimulus of dyspnea Hypoxia Less potent stimulus than hypercapnea Manning. NEJM, 1995.

Mechanisms Of Dyspnea: Stimulation Of Mechanoreceptors Upper airway Pulmonary receptors Limitations of movement exacerbate dyspnea The sensation of dyspnea varies with activation Chest wall receptors Restricted motion exacerbates dyspnea Redundant to pulmonary receptors Nausherwan. Chest, 2010.

Other Mechanisms Of Dyspnea Mechanical loading Changes in airway resistance, pulmonary or chest wall compliance Neuromechanical dissociation Air flow not equal to expected results of brain output Impaired oxygen utilization or delivery Anemia Increased CO -> EDP-> pulmonary edema Localized acidosis or resp muscle fatigue Deconditioning Poor cardiac and peripheral efficiency, early anaerobic metabolism and acidosis

Structural Approach Respiratory Cardiac Controller: depth and rate of breathing Ventillatory pump: movement of gas in and out of the alveolous Gas exchanger: pulmonary vasculature, alveoli Cardiac Anemia Deconditioning Heart failure

Most Common Causes of Dyspnea Asthma COPD ILD Cardiac disease

Differential Diagnosis of Dyspnea Cardiac Heart failure Coronary artery disease Arrhythmia Pericardial disease Valvular heart disease Pulmonary hypertension

Diagnosis of Dyspnea Pulmonary Chronis obstructive pulmonary disease Asthma Interstitial lung disease Pleural effusion Malignancy Bronchiectasis

Diagnosis of Dyspnea Non-cardiac/Non-pulmonary Thromboembolic disease Psychogenic Deconditioning Obesity Anemia GERD Metabolic conditions Cirrhosis Thyroid disease Neuromuscular Chest wall Upper airway

Approach To The Patient History and physical EKG Echocardiogram CXR/CT scan Spirometry Cardiopulmonary exercise testing

Differentiating Heart vs Lung Etiology 1586 patients presenting with dyspnea No clear heart failure Maisel. NEJM, 2002.

BNP Is Useful to Differentiate Heart Failure From Other Dyspnea Maisel. NEJM, 2002.

Case 1 A 30 year old woman presents with progressive exercise tolerance for the last 3 months. She ran a marathon at age 26, but now has shortness of breath walking up 1 flight of stairs. She denies chest pain, orthopnea or PND but has intermittent mild ankle edema.

Case1 Her blood pressure is normal and her exam is unremarkable. Her EKG and CXR are shown. What test should be ordered next? A treadmill stress test Pulmonary function testing A blood test for BNP A CT scan of the chest An echocardiogram

Electrocardiogram

Chest XR

Case 1 What test should be ordered next? A treadmill stress test Pulmonary function testing A blood test for BNP A CT scan of the chest An echocardiogram

Case 1 An echocardiogram is performed.

Echocardiogram

Case 1 The next best step is to: Start sildenafil 20 mg TID Send the patient for a right heart catheterization Send tests for rheumatologic disease Start an ACE Inhibitor

Hemodynamics RA (mmHg) 9 PA (mmHg) 92/44 (65) PCWP (mmHg) 7 CO (L/min) 3 PVR (Wood Units) 19

Right Sided Heart Failure Most commonly associated with left sided heart failure Pulmonary hypertension is another common cause

Patients Die From Right Heart Failure www.clarian.org/ADAM/doc/HealthIllustratedEncyclopedia/2/18131.htm www.mdconsult.com/das/patient/body/196982233-3/0/10041/35062.html

WHO Classification of PH Pulmonary arterial hypertension Idiopathic Heritable Drug/toxin induced Associated (HIV, CTD, CHD, schistosomiasis) I′. PVOD, PCH PH from left heart disease Systolic dysfunction Diastolic dysfunction Valvular disease PH from lung disease or hypoxemia ILD COPD OSA Altitude CTEPH Multifactorial Hematologic Systemic (sarcoid, vasculitis) Metabolic (glycogen storage) Other (tumor)

Localization of Abnormalities University of Michigan website Dijke. Nature Reviews Molecular and Cell Biology. 2007.

Right Heart Dysfunction Progression of PAH PAP PVR CO Time Pre-symptomatic/ Compensated Symptomatic/ Decompensating Symptom Threshold Right Heart Dysfunction Declining/ Decompensated CO =

Targets for Therapies in Pulmonary Arterial Hypertension Figure 1. Targets for Current or Emerging Therapies in Pulmonary Arterial Hypertension. Three major pathways involved in abnormal proliferation and contraction of the smooth-muscle cells of the pulmonary artery in patients with pulmonary arterial hypertension are shown. These pathways correspond to important therapeutic targets in this condition and play a role in determining which of four classes of drugs -- endothelin-receptor antagonists, nitric oxide, phosphodiesterase type 5 inhibitors, and prostacyclin derivatives -- will be used. At the top of the figure, a transverse section of a small pulmonary artery ( Humbert. NEJM, 2004.

Acute Pulmonary Embolism

Case 2 A 68 year old HTN, diabetic female presents with progressive shortness of breath over the last 5 years. She can walk about 2 blocks before needing to rest.

Case 2 The examination shows tachycardia and a normal blood pressure. There are bibasilar crackles and an S3 on exam.

EKG

Case 2 There was trace LE edema. The EKG shows LVH. An echocardiogram shows LVH and severe diastolic dysfunction.

Case 2 The next best step is: A nuclear stress test Aggressive blood pressure management A coronary angiogram Aggressive management of diabetes

Diastolic Heart Failure Nearly ½ of all patients with heart failure 65% 5 year mortality Shah. JAMA, 2008.

Typical Features Of Patients With Diastolic Heart Failure Female: 62-66% Elderly: mean age 72-74 Comorbidities CAD 36-53% HTN 55-77% AF 32-41% DM 32-45% CKD 23-26% Obesity Anemia

Mortality In Diastolic Heart Failure Is High 4596 patients over 15 years Owan. NEJM, 2006.

Diastolic Heart Failure: Elevated LV Filing Pressures Nagueh. JASE, 2009.

What Does DHF Look Like On Echo? Nagueh. JASE, 2009.

Treatment Treatment of comorbidities